Institute of Electrical and Electronics Engineers (IEEE) 802.11 is a set of air interface specifications in wireless local area network developed for Dedicated Short Range Communication (DSRC) by IEEE Committee. In IEEE 802.11 networking environment, a transmission rate of a physical layer is generally determined based on statistical data like packet retransmission rate, packet transmission error rate or packet reception error rate.
Determining the transmission rate based on packet retransmission rate and determining the transmission rate based on packet transmission error rate basically have the similar performance. For example, a method for determining the transmission rate based on the packet retransmission rate includes: a station (STA) or an access point (AP) determining a noisy level or a physical transmission performance of a channel by repeatedly sending physical layer protocol data unit (PPDU) data packets which have different rates, and further determining whether a current packet transmission rate of the physical layer needs to be raised or decreased based on the noisy level and/or the physical transmission performance.
The method above may have following disadvantages. On one hand, Detection of the noisy level of the channel may be relatively slow. On the other hand, even when the physical transmission performance of the channel is fine, if the channel is noisy (for example, a plurality of STAs and APs exist in the network), the STAs and the APs may collide with each other to result in noisy environment, which may cause an increased packet retransmission rate and a decreased physical layer rate of the STAs and APs transmitting PPDU. With the decreased physical layer rate, the STAs and APs may take more time to transmit packets. As a result, packets of the STAs and APs may be more prone to collide with each other. In this way, the physical layer rate of the STAs and APs transmitting PPDU is decreased continuously and reaches a minimum rate finally, and the packet retransmission rate may become greater, which leads to a zero throughput rate of the STAs and APs, and further leads to an interruption of communication.
A method for determining the transmission rate based on the packet reception error rate includes determining a noisy level or a physical transmission performance of a channel based on the packet reception error rate, which is an indirect estimation. The packet reception error rate in the method cannot directly reflect the physical transmission performance of the STAs and APs transmitting packets, the noisy level of the channel, and whether the channel is busy or clear. The packet reception error rate also cannot determine what influence the PPDU transmitted by the STAs and APs in different positions may cause to the reception performance of the STAs and APs. Thus, a throughput rate of the STAs or APs cannot be ensured.
From above, in existing techniques, the physical layer rate in the noisy channel environment may be decreased continuously and a throughput rate of the STAs or APs cannot be ensured effectively.